1. Field of the Invention
This invention relates to a subsea manifold system for selectively connecting a production line leading from a surface location remote from the manifold to one of a plurality of well lines leading to subsea oil and gas wells. In the environment in which this will be used, there will be many wellheads at spaced-apart locations from each other, for wells completed in the ocean floor. Production lines from each of these subsea wellheads will extend to the subsea manifold. Only one production line and one set of service lines will run from the manifold to the surface of the body of water.
2. Setting of the Invention and Prior Art
A large amount of the drilling of oil and gas wells is done in offshore water-covered areas. In the shallower water, wells are drilled and produced from platforms supported above the surface of the body of water by piles extending into the bottom of the water. In this system, drilling and production is carried on much like it is onshore. However, as the water depths become deeper, it becomes increasingly uneconomical to build such fixed platforms. Drilling of oil and gas wells is now being contemplated in water up to 1000 feet, or more. In one method of production, it is contemplated the wells will be drilled in the ocean floor and that the wellhead will be at the ocean floor instead of on the platform above the surface of the body of water. When wells are completed with the wellheads on the ocean floor, various means must be provided for lifting the oil and gas to the surface so that it may be utilized. One such system is described in U.S. Pat. No. 3,542,125, Phillip S. Sizer, inventor, issued Nov. 24, 1970. That patent describes a subsea wellhead system for servicing a plurality of wells having well-heads which are spaced apart and supported on a submerged platform. It includes a movable latch head selectively connectable with any one of the wellheads. The flow conductors connected to the outlet end of the latch head go to a remotely controlled location so that a workover tool, such as through the tubing (or pumpdown tools [PDT]) can be used. The wellheads to which the latch head is selectively connected will determine to which of the subsea wells the PDT tools are pumped. Thus, the movable latch head is selectively connected to the wellhead of the well which is to be serviced. Well tools are then pumped from a remote location service station through a latch head, to the selected wellhead, and to the selected well. A flow conductor is connected between the movable latch head and remotely located controlling service station. In the system of U.S. Pat. No. 3,542,125, the latch head must make a seal-tight connection with the selected wellhead. Applicant has disclosed a system whereby a sealing connection is not necessary.
Another patent of interest is U.S. Pat. No. 3,674,123, George E. Lewis, issued July 4, 1972. That patent relates to an apparatus enabling controllable diversion of tool passage between multiple pipes connectible with a single pipe and includes a housing forming a primary port in communication with a primary pipe to pass a pumpdown tool. The housing also forms a series of secondary ports respectively communicable with multiple secondary pipes selected to pass the tool. The rotor for driving the connector duct 21 and the housing is constructed so that the rotor is pressure balanced endwise. The connector duct within the housing is curved and is of a rigid configuration. These present features and accompanying problems which are not found in the present invention.